Sheet metal working tools



June 12, 1962 1 J. MORMANN SHEET METAL WORKING TOOLS Filed March 24,1960 /HVEN /b/T United States Patent @thee `Patented June l2, 19623,038,360 SHEET METAL WORKING TOOLS Lawrence J. Mormann, 601 2nd St. N.,La Crescent, Minn. Filed Mar. 24, 1960, Ser. No. 17,372 3 Claims. (Cl.81-15) 'I'his invention relates to new and useful improvements in sheetmetal working tools, and the principal object of the invention is toprovide a tool lwhich may be easily and conveniently used for deliveringimpacts on sheet metal for purposes of straightening, forming,deforming, or otherwise working the same.

As such, the tool in accordance with the invention is particularly wellsuited for automobile body work, `although the use thereof is by nomeans restricted to this environment. An important feature of theinvention resides in providing a tool of this type which may beeffectively utilized in poorly accessible locations and which, beingmanually actuated, is fully self-contained and does not requireconnection to external sources of energy such as electricity, compressedlair or hydraulic fluid.

Some of the advantages of theinvention reside in its simplicity ofconstruction, ease of operation, lightness of weight, durability Iand inits adaptability t-o economical manufacture.

With the above more important objects and features in view and suchother objects and features as may become apparent as this specicationproceeds, the invention will be understood from the followingdescription taken in conjunction with the accompanying drawings, whereinlike characters of reference are used to designate like parts, andwherein:

FIGURE l is a side elevational view of the invention;

FIGURE 2 is a fragmentary longitudinal sectional view thereof on anenlarged scale and showing the plunger in its projected position;

FIGURE 3 is a fragmentary sectional view, similar to that shown in theleft-hand portion 'of FIGURE 2, but illustrating the plunger in itsretracted position;

FIGURE 4 is a fragmentary sectional view, similar t0 that shown inFIGURE 2 but illustrating the cam member in a position where it is aboutto re-engage the cam surfaces of the plunger after the latter has beenretracted and returned to its projected position; and

FIGURE 5 is a fragmentary sectional view, taken substantially in theplane of the line 5-5 in FIGURE 2.

Referring now to the 'accompanying drawings in detail, the sheet metalimpact tool in accordance with the invention is designated generally bythe reference numeral and embodies in its construction a frame 11including a tubular member 12 provided at one end thereof with a hollowhead or housing 13 extending at right angles from the axis of the member12, as shown. An elongated bar member 14 has one end portion 14a thereofsuitably secured to the member 12, while the other end portion 14b ofthe member 14 is spaced away from the member 12 and disposed adjacentthe housing 13, as illustrated.

The housing 13 is equipped with an end plug 15 having an `axial bore 16therein which slidably receives a reciprocable plunger 17, the latterhaving a work engaging point or extremity 17a movable toward and awayfrom the bar member portion 14h. The lmem-ber portion 14b constitutes awork abutting or backing pad while the plunger delivers impacts againstthe work, as will ybe hereinafter described.

The lower end portion of the plunger, indicated at 17b, is rectangularin crosssection and slidable in a rectangular aperture formed in atransverse partition 1S in the housing 13, whereby the plunger isprevented from rotating. rl `he intermediate portion of the plunger isprovided with a collar or shoulder 19 anda compression spring 20 isinterposed between this shoulder and the partition 18, so as to Cil urgethe plunger outwardly, that is, toward the pad 14h, to the positionshown in FIGURE 2.

The lopposite sides of the plunger portion 17b are pro` vided withinclined grooves forming c-am surfaces 21 and the lower end of theportion 17b is also inclined so as to provide a cam surface 22. A cammember 23, suitably mounted at one end of an Vactuating rod 24, has aforked portion 23a which, as is -best shown in FIGURE 5, straddles theplunger portion 17b and terminates in a pair of inclined cam elements 25which are slidably receivable in the cam grooves of the plunger. The rod24 extends longitudinally through the frame member 12 and is connectedat its other end lby a pivot pin 26 to the lower end of and actuatingarm or lever 27, the upper end of the latter being fulcrumed vby a pivotpin 28 between a pair of transversely spaced, upstanding supports 29which lare provided rigidly on the frame member 12 adjacent the frameportion 14a. It is to be noted that the diameter of the frame member 12is substantially larger than that of the rod 24 and that the portion ofthe member 12 adjacent the lever 27 is provided with bearings 3d whichslida-bly receives the rod Kand retain the same substantiallycentralized in the frame member. However, the other end portion of therod 24, adjacent the plunger 17 is movable downwardly or depressiblefrom its centralized position in the frame member 12, it Ibeingunderstood that the rod 24 is suieiently rigid, yet exible enough topermit such downward deflection or depression to occur. Nevertheless,the inherent resiliency of the rod `2d returns the rod, afterdeilection, to its initial centralized position in the member 12, inwhich position the cam member 23 engages the underside `of kan `abutment31 `which is formed in the frame member 12 adjacent the housing 13.

When the tool is placed in use, it is applied to the work so that thearea of the work to ybe operated upon is disposed between the abutmentpad 14b and the extremity 17a of the plunger 17. Thereupon, whileholding the supports 29 in the palm of the hand, finger pressure isexerted on the lever 27 in the direction `of the arrow 32, thus causingthe rod 24 to slide inside the member 12 in the direction of the arrow33, and `also causing the elements 25 of the cam member 23 to slidealong the inclined cam surfaces 21, and retracting the plunger 17against the resilient action of the spring 20, and also compressing atapered, spiral compression spring 34 which is interposed `between thecam member 23 and an yannular shoulder 35 provided in the frame member12. When the cam member 23 reaches the position shown in FIGURE 3, theplunger is fully retracted and further sliding movement of the rod 24 inthe direction 33 causes the cam elements 25 to become disengaged fromthe cam surface 21 of the plunger, thus permitting the plunger to beforcibly projected by the spring 20 to deliver 4a positive impactagainst the work in abutment with the pad 14b.

When pressure on the lever `27 is relaxed, the spring 3'4 urges the rod24 and the cam member 23 to their initial position, but by that time theplunger 17 will have returned to its initial position so that it is notpossible for the cam element-s 25 to re-enter the cam grooves from thedirection in which they left them. However, during such return movement,the cam elements 25 will come into engagement with the cam surface `22of the plunger, with the result that the cam member 23 will -be forceddownwardly and the yadjacent end portion yof the rod 24 will lbedeflected accordingly. In so doing, the cam member 23 will pass underthe lower end of the plunger to the position shown in FIGURE 4, at whichpoint the cam elements 25 will clear the cam surface 22 of the plungerand will permit the cam member 23 to resume its initial, centralizedposition, with the cam elements 25 re-entering the cam grooves in theplunger from the left-hand side, as viewed in the drawings. The devicewill then be ready for the next cycle 3 of operation. Thus, byalternately pressing and releasing the lever 27, 'the plunger 1.7 may becaused to deliver a series of impacts against the work to performwhatever operation may be intended.

While in the foregoing there has been shown and described the preferredembodiment of the invention, various modifications may become apparentto those skilled in the art to which the invention relates. Accordingly,it is not desired to limit the invention to this disclosure and variousmodifications may be resorted to, such `as may lie within the spirit`and scope of the appended claims.

What is claimed as new is:

1. In a sheet metal impact tool, the combination of a frame including anelongated hollow main frame member and an elongated hollow headconnected to one end of said frame member in perpendicular relationtherewith, a projeotable and retractable work engaging plungerreciprocable longitudinally in said head, and means for actuating saidplunger, said actuating means comprising resilient means in the head forurging said plunger to its projected position, a reciprocable actuatingrod extending longitudinally in said frame member `and having inner andouter ends, means lat lthe outer end of said rod for reciprocating t-hesame, a fork provided at the inner end of the rod and straddling saidplunger, said plunger being provided at opposite sides thereof with apair of inclined grooves offset by an acute angle from` the axis ofreciproca tion of said rod, and la pair of inturned cam elementsprovided on the furcations of said fork and slid-ably engaging saidgrooves whereby to retract the plunger against the action of saidresilient means when the rod is moved outwardly in the frame member,ysaid `cam elements being disengaged from said grooves at the youter endof the rod movement whereby to release the plunger for projection bysaid resilient means.

2. The device as dened in claim 1 wherein said plunger is provided withan inclined end surface adjacent and substantially parallel to saidgrooves, said cam elements of said fork being engageable with saidinclined end surface during inward movement of said rod in said framemember and the inner end portion lof the -rod being laterallydeiiectable in the plane of said plunger during such move-l ment wherebysaid fork may by-pass said plunger end for re-engagement of said camelements with said grooves while the plunger `remains relativelystationary.

3. The device as defined in claim Z together with resilient meansprovided in said main frame member in engagement with said fork forurging the latter toward said plunger.

Cox Aug. 30, 1932 Ristow Mar. 17, 1959

